HMS Simoom (P225)

Schematic drawing of a S-class submarine

The S-class submarines were designed to patrol the restricted waters of the North Sea and the Mediterranean Sea. The third batch was slightly enlarged and improved over the preceding second batch of the S class. The submarines had a length of 217 feet (66.1 m) overall, a beam of 23 feet 9 inches (7.2 m) and a draught of 14 feet 8 inches (4.5 m). They displaced 865 long tons (879 t) on the surface and 990 long tons (1,010 t) submerged.[1] The S-class submarines had a crew of 48 officers and ratings. They had a diving depth of 300 feet (91 m).[2]

For surface running, the boats were powered by two 950-brake-horsepower (708 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650-horsepower (485 kW) electric motor. They could reach 15 knots (28 km/h; 17 mph) on the surface and 10 knots (19 km/h; 12 mph) underwater.[3] On the surface, the third-batch submarines had a range of 6,000 nautical miles (11,000 km; 6,900 mi) at 10 knots (19 km/h; 12 mph) and 120 nmi (220 km; 140 mi) at 3 knots (5.6 km/h; 3.5 mph) submerged.[2]

The boats were armed with seven 21-inch (533 mm) torpedo tubes. A half-dozen of these were in the bow, and one external tube was mounted in the stern. They carried six reload torpedoes for the bow tubes for a total of thirteen torpedoes. Twelve mines could be carried in lieu of the internally stowed torpedoes. They were also armed with a 3-inch (76 mm) deck gun.[4] It is uncertain if Simoom was completed with a 20-millimetre (0.8 in) Oerlikon light AA gun or had one added later. The third-batch S-class boats were fitted with either a Type 129AR or 138 ASDIC system and a Type 291 or 291W early-warning radar.[5]

HMS Simoom was a third-group S-class submarine and was ordered by the British Admiralty on 2 September 1940. She was laid down in the Cammell Laird Shipyard in Birkenhead on 14 July 1941 and launched on 12 October 1942.[6] On 27 December 1942, Simoom, under the command of Lieutenant Christopher Henry Rankin, sailed from the shipbuilding yards to Holy Loch, where she was commissioned into the Royal Navy three days later.[6][7] The simoom is a hot dry desert wind; Simoom was the fifth Royal Navy ship with this name.[8]

After training, Simoom departed port on 15 February 1943 for a patrol off Norway, providing protection to Arctic Convoys to and from ports in Northern Russia. Her patrol was uneventful, and she returned to Lerwick on 11 March. After having one of her propellers changed, Simoom sailed to Gibraltar, then on to Algiers, where she arrived on 24 May.[7]

Algiers

On 4 June 1943, Simoom, now under the command of Lieutenant Geoffrey D. N. Milner, departed Algiers to patrol west of Sardinia and Corsica. Her patrol was again uneventful, and she returned to port on 17 June having sighted only a few aircraft and no ships.[7]

Simoom's next patrol started on 28 June, when she patrolled in the Tyrrhenian Sea to provide cover for the Allied landings in Sicily. On 13 July, she fired four torpedoes at an enemy convoy, but missed. Two days later, the submarine attacked the Italian tug Robusto with her deck gun on the surface and scored several hits, but an approaching aircraft forced her to break off the action and submerge. Simoom then ended her patrol on 22 July.[7]

Vincenzo Gioberti blowing up after being hit by torpedoes from Simoom

Simoom again departed Algiers on 4 August for a patrol in the Gulf of Genoa; on 8 August, she unsuccessfully attacked a merchant ship with three torpedoes. The next day, the boat sighted the Italian cruiser Giuseppe Garibaldi along with several light cruisers and destroyers; she fired three torpedoes at Giuseppe Garibaldi, but again missed. The torpedoes, however, instead sank the Italian Oriani-class destroyer Vincenzo Gioberti (it) with the loss of 171 men.[9] Simoom was then counter-attacked with depth charges, but she evaded damage and returned to Algiers on 13 August after having been recalled.[7]

On 3 September, the submarine commenced another patrol in the western Mediterranean, with orders to act as a directional radio beacon during Operation Avalanche, the Allied landings near Salerno. Simoom's participation was not necessary, and she did not carry out the operation. On 15 September, the boat launched two torpedoes at the German transport KT 11, but missed. She then ended her patrol in Algiers on 22 September.[7]

During her service with the Royal Navy, Simoom sank one Italian destroyer of 1,685 tons.[7]

Date	Name of ship	Tonnage	Nationality	Fate and location
9 August 1943	Vincenzo Gioberti	1,685	Kingdom of Italy	Torpedoed and sank at 44°04′N 09°32′E

• Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 978-1-904381-05-1.
• Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 978-0-87021-962-7.
• Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 978-0-85177-146-5.
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• Heden, Karl Eric (2006). Sunken Ships, World War II: U.S. Naval Chronology Including Submarine Losses of the United States, England, Germany, Japan, Italy. History Reference Center: Branden Books. ISBN 0828321183.
• McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. 129. Oxford, UK: Osprey Publishing. ISBN 978-1-84603-007-9.